1996 ACURA RL KA9 engine

Troubleshooting Flowchar t
Check fo r a n ope n o r shor t i n th e
wir e (BA T line) :
Measur e voltag e betwee n th e
PGM-F I mai n rela y 4 P connecto r
termina l No . 3 an d bod y ground .
I s ther e batter y voltage ?
YES
Chec k fo r a n ope n o r shor t i n th e
wir e (IGS W line) :
1 . Tur n th e ignitio n switc h O N (II) .
2 . Measur e voltag e betwee n th e
PGM-F I mai n rela y 8 P connec -
to r termina l No . 5 an d bod y
ground .
I s ther e batter y voltage ?
YES
(To pag e 11-148 ) PGM-F
I MAI N RELA Y 8P CONNECTO R (C433 )
Wir e sid e o f femal e terminal s
NORepai r ope n in th e wir e betwee n
th e PGM-F I mai n rela y an d G10 1
(locate d a t middl e o f engine) .
NO
Repai r ope n o r shor t i n th e
wir e betwee n th e PGM-F I
mai n rela y an d th e No . 6 EC U
(PCM ) (2 0 A ) fuse .
Replac e th e No . 6 EC U (PCM )
(2 0 A ) fus e in th e under-das h
fuse/rela y box . PGM-F
I MAI N RELA Y 4P CONNECTO R (C432 )
Wir e sid e o f femal e terminal s
NO
Repai r ope n o r shor t i n th e
wir e betwee n th e PGM-F I
mai n rela y an d th e No . 2 2
FUE L PUM P (2 0 A ) fuse .
Replac e th e No . 2 2 FUE L PUM P
(2 0 A ) fus e in th e under-das h
fuse box .
YES
Is ther e continuity ?
Engin
e wil l no t start .
Inspectio n o f PGM-F I mai n
rela y an d rela y harness .
Chec k fo r a n ope n in th e wir e (PG 1
line) :1. Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e PGM-F I mai n
rela y 4 P connecto r an d 8 P
connector .
3 . Chec k fo r continuit y betwee n
th e PGM-F I mai n rela y 8 P
connecto r termina l No . 7 an d
bod y ground .
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Intake Air System

System Description

The system supplies air for all engine needs. It consists of the intake air pipe. Air Cleaner, intake air duct. Throttle Body,

Idle Air Control (IAC) Valve, idle air control thermal valve, and intake manifold.

A resonator in the intake air pipe provides additional silencing as air is drawn into the system.

IMRC SOLENOID VALVE 2

IMRC

SOLENOID

VALVE 1
IMRC

VACUUM

TANK

From No. 20 ECU

(PCM)
(20 A)

FUSE

(in the under-dash

fuse/relay box)

IMRC

DIAPHRAGM

VALVE 1
VARIOUS

SENSORS

THROTTLE BODY
INTAKE

AIR

DUCT
INTAKE

MANIFOLD
IDLE

ADJUSTING

SCREW
With

TCS

IDLE AIR

CONTROL

THERMAL

VALVE
IAC

VALVE
From PGM-FI

MAIN RELAY

IMRC

DIAPHRAGM

VALVE 2
IMRC

CHECK

VALVE

ENGINE

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Throttle Bod y
Descriptio n
The throttl e bod y i s a single-barre l side-draf t type . Th e
lowe r portio n o f th e throttl e valv e i s heate d b y engin e
coolan t fro m th e cylinde r head . Th e idl e adjustin g screw ,
whic h increases/decrease s bypas s air , an d th e Evapora -
tiv e Emissio n (EVAP ) Caniste r por t ar e locate d o n th e to p
of th e throttl e body .
THROTTL E
POSITIO N
(TP)SENSO R
IDLE ADJUSTIN GSCREW
THROTTL EVALVE
THROTTL ESTOPSCRE W(Do no t adjust. )
Inspectio n
1 . Disconnec t th e vacuu m hos e (t o th e EVA P canister )
fro m th e to p o f th e throttl e body ; connec t a vacuu m
gaug e t o th e throttl e body .
VACUU M PUMP/GAUGE , 0 - 3 0 in.H g
A973 X - 04 1 - XXXX X
2. Allo w th e engin e t o idle , an d chec k tha t th e gaug e
indicate s n o vacuum .
I f ther e i s vacuum , chec k th e throttl e cabl e (se e
pag e 11-154 ).
3 . Chec k tha t vacuu m is indicate d o n th e gaug e whe n
the throttl e is opene d slightl y fro m idle .
If th e gaug e indicate s n o vacuum , chec k th e throttl e
bod y port . I f th e throttl e bod y por t i s clogged , clea n
i t wit h carbureto r cleaner .
4 . Sto p th e engine , an d chec k tha t th e throttl e cabl e
operate s smoothl y withou t bindin g o r sticking .
I f ther e ar e an y abnormalitie s i n th e abov e steps ,
chec k for .
• Excessiv e wea r o r pla y i n th e throttl e valv e shaft .
• Stick y o r bindin g throttl e leve r a t ful l clos e posi -
tion.
• Clearanc e betwee n throttl e sto p scre w an d throt -
tl e leve r a t th e full y close d position .
There shoul d b e
n o clearance .
THROTTL E LEVE R
THROTTL E
LEVER
THROTTL E STO P SCRE W
(D o no t adjust. )
Replace th e throttl e bod y i f ther e i s excessiv e pla y
i n th e throttl e valv e shaf t o r i f th e shaf t i s bindin g o r
sticking .
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Intake Manifol d Runne r Contro l (IMRC ) Syste m
Descriptio n
Satisfactor y powe r performanc e i s achieve d b y closin g an d openin g th e intak e manifol d runne r contro l (IMRC ) valves .
Hig h torqu e a t lo w RP M is achieve d whe n th e valve s ar e closed , wherea s hig h powe r a t hig h RP M is achieve d whe n th e
valve s ar e opened .
INTAKE MANIFOL D RUNNE R CONTRO L
(IMRC ) SOLENOI D VALV E 1 OF F INTAK
E MANIFOL D RUNNE R CONTRO L
(IMRC ) SOLENOI D VALV E 2 OF F
ENGIN E SPEE D IS ABOV E 3,20 0 rp m
ENGINE SPEE D IS ABOV E 3,80 0 rp m
IMR C SOLENOI D VALV E 2
IMR C
SOLENOI D
VALVE !
IMR C
DIAPHRAG M 1
VARIOU SSENSOR S
IMRC
VALVE 1: CLOSED IMRC
VALVE 2: CLOSED
IMR C
VALV E 2
IMR C
DIAPHRAG M 2
IMR C
VALV E 1 IMR
C
DIAPHRAG M 1
IMR C
VALV E 1 : OPE N
IMR C
VALV E 2 : CLOSE D IMR
C
VALV E 1 : OPE N
IMR C
VALV E 2 : OPE N
From No . 2 0 EC U(PCM ) (20 A )FUS E
(i n th e under-das h
fuse/rela y box )
Fro
m PGM-F I
MAI N RELA Y
IACVALV E
ENGIN ECOOLAN T
VACUU
M
RESORVOI R
IMRC
DIAPHRAG M 2 VACUU
M
CHECKVALV E
INTAK E
MANIFOL DTHROTTL
E BOD Y
IDL
E AI R
CONTRO L
THERMA L
VALVEIDLEADJUSTIN GSCREWINTAK EAIRDUC T
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Intake Ai r Bypas s Contro l Syste m
Descriptio n
Th e Intak e Ai r Bypas s Contro l syste m enable s fres h ai r
t o b e draw n throug h th e throttl e bod y an d fue l injecto r
port.
INJECTO R
AI R FLO W FRO M TH E
IDL E AI R CONTRO L THERMA L VALV E
Testing
1 . Star t th e engine . Hol d th e engin e a t 3,00 0 rp m wit h
n o loa d i n Par k o r neutra l until the radiato r fa n
come s on .
2 . Disconnec t th e vacuu m hose s an d connec t vacuu m
pum p t o th e hose s individually .
VACUUM PUMP /GAUGE , 0 - 3 0 In.H gA973 X - 04 1 -
XXXX X
3. Allo w th e engin e t o idle , an d chec k th e vacuum .
• I f n o vacuum , chec k th e vacuu m hos e routin g o f
th e intak e ai r bypas s contro l system .
• I f th e vacuum , chec k th e IA C Valv e (se e pag e
11-115 ), th e Idl e Ai r Contro l Therma l Valv e (se e
pag e 11-123 ) an d th e intak e manifol d port . I f th e
intak e manifol d por t i s clogged , clea n it wit h car -
bureto r cleaner .
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Emission Contro l Syste m
System Descriptio n
The emissio n contro l syste m include s a Thre e Wa y Cata -
lyti c Converte r (TWC) , Exhaus t Ga s Recirculatio n (EGR )
system , Positiv e Crankcas e Ventilatio n (PCV ) syste m an d
Evaporativ e Emissio n (EVAP ) system . Th e emissio n contro l
syste m is designe d t o mee t federa l an d stat e emissio n
standards .
Tailpipe Emissio n
Inspection
Do no t smok e durin g thi s procedure . Kee p
an y ope n flam e awa y fro m you r wor k area .
1 . Star t th e engine . Hol d th e engin e a t 3,00 0 rp m wit h
n o loa d (i n Par k o r neutral ) unti l th e radiato r fa n
come s on , the n le t i t idle .
2 . Connec t a tachometer .
3 . Chec k an d adjus t th e idl e speed , i f necessar y (se e
pag e 11-124 ).
4 . War m u p an d calibrat e th e C O mete r accordin g to th e
mete r manufacturer' s instructions .
5 . Chec k idl e C O wit h th e headlights , heate r blower ,
rea r windo w defogger , coolin g fan , an d ai r condition -
er off .
NOTE : (Canada ) Depres s th e parkin g brak e pedal .
Star t th e engine , the n chec k tha t th e headlight s ar e
off.
CO mete r shoul d indicat e 0.1 % maximum .
Three Wa y Catalyti c Converte r
(TWC)
Descriptio n
Th e Thre e Wa y Catalyti c Converte r (TWC) is use d t o
conver t hydrocarbon s (HC) , carbo n monoxid e (CO) , an d
oxide s o f nitroge n (NOx) in th e exhaus t gas , t o carbo n
dioxid e (CO
2), dinitroge n (N2) an d wate r vapor .
SECONDAR Y HEATE D OXYGE N SENSO R (SENSO R 2)
HOUSIN G
THREE WA Y
CATALYST S
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The sca n too l indicate s Diagnosti c Troubl e Cod e (DTC ) P0420 : Catalys t syste m efficienc y belo w threshold .
Descriptio n
This syste m evaluate s th e catalyst' s capacit y b y mean s o f th e HO2 S (Primar y an d Secondary ) outpu t durin g stabl e drivin g
conditions . I f deterioratio n ha s bee n detecte d durin g tw o consecutiv e drivin g cycles , th e MI L come s o n an d DT C P042 0 wil l
be stored .
NOTE : I f som e o f th e DTC s liste d belo w ar e store d a t th e sam e tim e a s DT C P0420 , troubleshoo t thos e DTC s first , the n
troubleshoo t DT C P0420 .
P0136 , P0139 : Secondar y HO2 S
P0141 : Secondar y HO2 S Heate r
Possibl e Caus e
• TW C Deterioratio n
• Exhaus t syste m leakag e
Troubleshootin g Flowchar t
— Th e MI L ha s bee n reporte d on .
— DT C P042 0 is stored .
Proble m verification :
1 . D o th e PC M Rese t Procedure .
2 . Star t th e engine . Hol d th e
engin e a t 3,00 0 rp m wit h n o
loa d (i n Par k o r neutral ) unti l
th e radiato r fa n come s on .
3 . Connec t th e AC S servic e con -
nector .
4 . Test-driv e 4 0 - 5 5 mp h (6 4 -
8 8 km/h ) fo r approx . 2 min -
utes . The n decelerat e fo r a t
leas t 3 second s wit h th e throt -
tl e completel y closed . The n
reduc e th e vehicl e spee d t o
3 5 mp h (5 6 km/h) , an d tr y t o
hol d it unti l th e readines s cod e
come s on .
I s DT C P042 0 indicated ?
YES
Chec k th e TW C (se e sectio n 9 ).
I f necessary , replac e th e TWC . Intermitten
t failure , syste m is O K
at thi s time .
NO
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Emission Contro l Syste m
Exhaus t Ga s Recirculatio n (EGR ) Syste m (cont'd )
The sca n tool indicate s Diagnosti c Trouble Code (DTC ) P1491 : An insufficien t lift of th e Exhaus t Gas Recirculatio n
(EGR) valve .
Is DT C P149 1 indicated ?
YES
Chec k fo r vacuu m to th e EG Rvalve :1. Disconnec t th e No . 1 1 hos e fro m
th e EG R valve .
2 . Connec t vacuu m pump/gaug e
t o th e hose .
3 . Star t th e engin e an d le t i t idle .
I s ther e an y vacuum ?
YES
Chec k fo r a malfunctio n i n th e
EG R valv e vacuu m contro l
solenoi d valve :
1 . Disconnec t th e contro l bo x 4 P
connector .
2 . Rechec k th e No . 1 1 hos e fo r
vacuum .
(T o pag e 11-169 )
Intermitten t failure , syste m is O Kat thi s time . Chec k fo r poo r con -
nection s o r loos e wire s a t C251 ,
C25 4 (locate d a t lef t shoc k tower) ,
C107 (EG R valve ) an d PCM .
NOVACUU M PUMP/GAUGE , 0 - 3 0 in.H g
A973 X - 04 1 - XXXX X
No. 1 1 VACUU M
HOSE
(To pag e 11-169 )
EGRVALV E
NO
Proble m verification :
1 . D o th e PC M Rese t Procedure .
2 . Connec t th e SC S servic e con -
nector .
3. Star t th e engine . Hol d th eengin e a t 3,00 0 rp m wit h n o
loa d (i n Par k o r neutral ) unti l
th e radiato r fa n come s on .
4 . Driv e th e vehicl e o n th e roa d fo r
approx . 1 0 minutes . Tr y to kee p
th e engin e spee d i n th e 1,70 0 -
2,50 0 rp m range .
Th
e MI L ha s bee n reporte d on .
DT C P149 1 is stored .
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